Basically you are remapping the colours, so anything that was green in shot will now be blue. If this was an optical printing error originally (i.e. they optically screwed up and ended up with green rather than blue) then this would actually correct the anomolies in the whole frame. If not (i.e. they just coloured in the sabre green by mistake) then you are adjusting the colour balance of the shot away from the original.
There is hardly any bright green elsewhere in the scene, so you could probably get away with it anyway.